Wheel Controller 3D is a complete alternative to Unity's inbuilt WheelCollider. It allows for more realistic vehicle behavior, complete customization, and 3D ground detection.

Arcade car controller Multiplayer: asset with arcade car physics, well suited for mobile projects.

Arcade car controller: asset with arcade car physics, well suited for mobile projects.

NWH Vehicle Physics 2 is a complete vehicle simulation package for Unity. Realistic, easy to use and heavily customizable.